-- http://www.scriptspot.com/forums/3ds-max/general-scripting/when-changes-do

(	
	global Ar_Hpoint = #() 
	global Ar_Line = #()
	global Ar_All = #(Ar_Hpoint, Ar_Line)

	Fn ADDpoint &ArrayA = --- & means in/out paramiter
	(
		local p = point box:true cross:false size:20 constantscreensize:false
		append ArrayA p
	)

	Fn drawLineBetweenTwoPoints pointA pointB &ArrayC = --- & means in/out paramiter
	(   
		local s = SplineShape pos:pointA
		append ArrayC s
		addNewSpline s
		addKnot s 1 #corner #line PointA
		addKnot s 1 #corner #line PointB
		updateShape s
	)

	ADDpoint &Ar_Hpoint 
	ADDpoint &Ar_Hpoint 
	move Ar_Hpoint [2] [50,0,0]
	ADDpoint &Ar_Hpoint 
	move Ar_Hpoint [3] [100,0,0]

	drawLineBetweenTwoPoints Ar_Hpoint[1].pos Ar_Hpoint[2].pos &Ar_Line
	drawLineBetweenTwoPoints Ar_Hpoint[2].pos Ar_Hpoint[3].pos &Ar_Line
	
--------- NEW PART ---------
	
	local str = stringStream ""
	
	for i = 1 to 2 do (
		format "when transform Ar_Hpoint[%] changes do (setKnotPoint Ar_Line[%] 1 1 Ar_Hpoint[%].pos ; updateShape Ar_Line[%])\n" i i i i to:str
		format "when transform Ar_Hpoint[%+1] changes do (setKnotPoint Ar_Line[%] 1 2 Ar_Hpoint[%+1].pos ; updateShape Ar_Line[%])\n" i i i i to:str
	)
	
	execute(str as string)
	
--first part
/*
when transform Ar_Hpoint[1] changes do (setKnotPoint Ar_Line[1] 1 1 Ar_Hpoint[1].pos ; updateShape Ar_Line[1])
when transform Ar_Hpoint[2] changes do (setKnotPoint Ar_Line[1] 1 2 Ar_Hpoint[2].pos ; updateShape Ar_Line[1])
when transform Ar_Hpoint[2] changes do (setKnotPoint Ar_Line[2] 1 1 Ar_Hpoint[2].pos ; updateShape Ar_Line[2])
when transform Ar_Hpoint[3] changes do (setKnotPoint Ar_Line[2] 1 2 Ar_Hpoint[3].pos ; updateShape Ar_Line[2])
*/

--second part
/*
for i = 1 to 2 do  (
when transform Ar_Hpoint[i] changes do (setKnotPoint Ar_Line[i] 1 1 Ar_Hpoint[i].pos ; updateShape Ar_Line[i])
when transform Ar_Hpoint[i+1] changes do (setKnotPoint Ar_Line[i] 1 2 Ar_Hpoint[i+1].pos ; updateShape Ar_Line[i])
)
*/

--third part
/*
for b=1 to 2 do (
global i=b
when transform Ar_Hpoint[i] changes do (setKnotPoint Ar_Line[i] 1 1 Ar_Hpoint[i].pos ; updateShape Ar_Line[i])
when transform Ar_Hpoint[i+1] changes do (setKnotPoint Ar_Line[i] 1 2 Ar_Hpoint[i+1].pos ; updateShape Ar_Line[i])
)
*/
	
)